Coffee management in the dry season: watering, mulching and tree recovery

The 5-month dry season in the Central Highlands determines whether the coffee tree has enough strength for the next flowering season. Instructions on how to irrigate properly, mulch to retain moisture, and recover after drought — combining Dak Lak experience and WASI recommendations.

Summary: The dry season in the Central Highlands, which lasts from November to April next year, is the longest and harshest period for Robusta coffee trees. Wrong watering or leaving out mulching one season can cause the plant to "go dormant" for half the year — not dead but not productive. This article summarizes 4 big things to do according to the dry season timeline, based on the guidance of the WASI Institute and actual observations in the orchards of Dak Lak and Gia Lai.

Applies to: Robusta + Arabica Catimor coffee in the Central Highlands (Dak Lak, Lam Dong, Gia Lai, Dak Nong, Kon Tum). Business tree 4 years old or older.
Duration: About 5 months, from November to April.
Difficulty level: Medium. The decision depends heavily on terrain + water source.
Estimated additional costs: 5-12 million/ha (mainly pumped fuel + covering materials).

What is special about the dry season in the Central Highlands

Unlike the dry season in the West or the Central region, the dry season in the Central Highlands has 3 characteristics that create dual pressure on coffee:

Laos wind lasts from December to March, air humidity often drops to 35-40%, coffee leaves evaporate water twice as fast.
Day-night difference of 12-15°C in the highlands of Dak Lak, Lam Dong — trees must continuously regulate themselves.
Red basalt soil layer is 2-5m thick, highly organic but has an airy structure, loses water quickly if not covered.

Plus: by the end of December and early January, the trees have been harvested, preparing to raise flower buds for the next season. If the plant lacks water or is stressed at this time, the flower buds will dry out and become black, resulting in a 30-50% decrease in yield in the next crop. There is no quick way to "save" — you have to do it right from the beginning of the dry season.

Prepare from October (end of the rainy season)

[ ] Check water sources: wells, reservoirs, ditches. Measure the reserve — is it enough to irrigate at least 3 times × actual area?
[ ] Inspect the roots of a few representative trees. Roots function well = white, with root hairs. Yellow / dark roots = the tree is in decline.
[ ] Clean roads, ditches, and irrigation equipment. Fix leaking nozzles/faucets first, not while they are dry.
[ ] Reserve covering materials: dry grass, composted coffee husks, straw — 5-8 m³/ha is about right.
[ ] Cut diseased branches, ineffective branches, and branches close to the ground after harvesting. Let the tree focus on recovery.

Any tree that is already showing signs of decline (widespread yellow leaves, poor roots) — don't wait for the dry season to treat it. October-November is still wet, apply 5-8 kg/tree of organic fertilizer + root stimulation immediately.

Four things according to the dry season timeline

November-December: Start watering + rooting

Irrigate the first time when the soil at the root layer (20-30cm deep) begins to dry slightly. Don't wait for the plant's leaves to wilt before watering it — by then the plant has lost 5-7% of its potential yield.

First watering dose for commercial crops:

Dak Lak red basalt soil: 400-500 liters/tree.
Gray granite / gneiss soil: 300-400 liters/tree.
Lam Dong ancient alluvial soil: 350-450 liters/tree.

Water slowly every 30-45 minutes/plant, do not water loudly. After watering, fill the soil around the base with fine soil mixed with rotten coffee husks — both to retain moisture and reduce erosion when watering next time.

December-February: Peak of dry season — watering flower sprouts

This is the 3 months that decide the flower buds. The rule I keep telling you:

Irrigate the second phase about 20-25 days after the first phase. Immediately watch for crab sprouts appearing on the silk branches.
When the crab sprouts are bright and clear, water deeply once (450-550 liters/plant) to stimulate flowers to bloom simultaneously. The Robusta crop needs moist rain 5-7 days after this irrigation — if there is no rain, light additional irrigation.
After the flowers bloom → reduce watering by 30%, leave the pollinated plants alone. Watering vigorously right at the time of bloom causes flowers to drop en masse.
The 3rd and 4th phases are 25-30 days apart depending on the moisture level in the root layer.

Warning about sprinkler irrigation: many orchards use sprinklers to sprinkle the whole orchard for convenience. In Lao wind, the evaporation rate of spray water can be 30-40% before reaching the ground. Watering the root directly (drip, basin around the root) is 2-3 times more effective.

Covering — cheapest investment, biggest savings

A 5-8cm layer of dry grass or decomposed coffee pods around the base (leaving 10cm around the root collar) reduces soil evaporation by 40-60%. I'm still surprised how many orchards skip this step.

Rules:

Spread the mulch as wide as the tree canopy, not just around the base.
Leave the root collar open 10-15cm — high temperature + humidity at the root collar is where the fungus destroys the fastest.
Materials must be damaged. Fresh grass or green straw will absorb N from the soil when decomposing → plants lack nitrogen.
Do not use plastic mulch — it looks beautiful but the soil holds air and the roots suffocate.

A orchard with 100 trees/hectare covered properly saves 30-40% of irrigation water compared to an open orchard. Calculate the cost of pumping fuel + irrigation, the mulch "repays capital" after 1 season.

Recovery from dryness — March-April

At the end of the dry season, many coffee leaves often fall, and some branches dry at the tips. This is the time:

Cut off dry and diseased branches — but gently. Don't cut deeply before the tree has recovered.
Apply 3-5 kg/tree of organic fertilizer around the canopy (not close to the base).
Spray leaves with amino acid + trace elements (Zn, B) once to stimulate new buds.
DO NOT apply strong chemical fertilizers when the tree has not yet budded. Shock tree.

Wait until the first rain of the season (usually mid-April to May) to apply the first round of NPK for the new crop.

Check every 10-14 days

[ ] Damp soil at root layer (20-30cm deep). The plant needs moderate humidity, not dry or cracked.
[ ] Leaf color: dark green = OK. Slight yellowing at the tip = about to need watering. Yellow + curved = seriously lacking water.
[ ] Signs of root mealybugs: strip the mulch to check the root collar. The dry season is the season when mealybugs + nematodes thrive.
[ ] Condition of crab sprouts and flowers: count the number of branches with sprouts to predict yield.
[ ] Save water: record the amount of water each watering session, compare with the previous one.

Three costly mistakes

Watering too little and then watering too much: Plants are constantly stressed by moisture, small dead roots, and wilted leaves. When watering again, the plant does not have time to absorb it, the water flows to the deep layer and is wasted.

Application of urea during the dry season to "preserve leaves": Counterproductive. Urea needs water to dissolve, not enough in the dry season → roots burn or evaporate. The dry season is the season for potassium and organic matter, not nitrogen.

Spray heavily during the flowering stage: Coffee flowers are very sensitive. Spray when the plant sheds pistils = mass flower drop. If you must spray (eg disease prevention), do it 5-7 days before or after the hatching period.

Other common errors

Irrigation according to mechanical schedule, not checking actual soil moisture.
Removing coverage because it's "unnecessary" — this is a hidden costly mistake.
Not pruning branches for pests and diseases at the beginning of the season → pathogens accumulate, causing an outbreak next season.
Believe the introduction of multi-nutrient "miracle fertilizer" instead of looking at specific plants + soil.
Forcing plants to flower too early by watering them before Tet to make the flowers look beautiful. The tree is exhausted for the main crop.

Dry season diary

For each irrigation session, record:

Irrigation date + start/end time.
Estimated water volume (running hours × nozzle capacity).
Leaf + soil condition BEFORE watering.
Materials for mulching and mulching — type + volume.
Observe crab sprouts, flowers, and new buds after 5-7 days.

At the end of the dry season (April), summary:

Total amount of water irrigated / ha.
Number of irrigation cycles.
Percentage of plants with good flower buds (count 30 random plants).
Problems have occurred: mealybugs, nematodes, local wilt, etc.

This data is much more valuable than "common experience". Next year you will know if you watered enough and if you need to adjust.

References

*Technical process for taking care of Robusta coffee in the business stage* — Central Highlands Agricultural and Forestry Science and Technology Institute (WASI), 2016 updated 2023.
*Recommendations for fertilizing coffee according to soil analysis results* — IPI (International Potash Institute), 2015.